By MANOHLA DARGIS

August 1, 2013

At once beautifully realized and brutally uncompromising, “Our Children” opens with a young woman weeping. She’s a lovely young thing, her features almost obscured by the grayness of her skin, the puffiness around her eyes and the oxygen tubes threaded into her nose. “You’ll bury them in Morocco,” she says to someone hovering nearby and then, as her tears begin to fall, she repeats her appeal. The intensity of the plea is a tug at the heart, a tug that turns into a jolt with a blunt cut to four little coffins being loaded on a plane.

The reason for her weeping seems unambiguous, but the story that the Belgian director Joachim Lafosse tells turns out to be anything but obvious. After its shocker opening, the movie effectively begins anew, this time with a cut to the young woman, Murielle (Émilie Dequenne), moaning in ecstasy. She’s in the embrace of her lover, Mounir (Tahar Rahim), a young man with whom she is having a passionate, powerfully physical affair. Youth radiates from the couple, and the fact that they’re fumbling in a car like teenagers who have nowhere else to go only emphasizes their age. Shot with a hovering camera that at first conveys intimacy that grows increasingly and intentionally intrusive, this and the playful scenes that follow convey a warmth that rapidly draws you in.

Tahar Rahim and Émilie Dequenne in the drama “Our Children,” a Joachim Lafosse film in which a couple’s bliss cracks under pressure.

DistriB Films

Mr. Lafosse, who shares screenwriting credit with Matthieu Reynaert and Thomas Bidegain, moves the story forward just as quickly. After a few preliminaries, Murielle weds Mounir, moving into the house he has long shared with an older, well-established doctor, André Pinget (Niels Arestrup). An enigmatic figure whose mysteries peel away slowly, André scarcely seems interested in Murielle even when she eagerly tries to impress him. Her anxiety is understandable; he’s something of a father figure to Mounir, who treats him with deference bordering on obsequiousness. For years, André has been taking care of Mounir and his relatives, both with money and immigration help, which might register as altruistic if Mounir didn’t seem so anxious and André so controlling.

He can’t be called domineering at least at first, just exacting and a bit spoiled. There’s an old-fashioned patrician air about him that registers as charming one minute and overbearingly paternalistic the next. If Murielle doesn’t seem to mind, it’s partly because she doesn’t have much of a family and, like Mounir, she very much wants to please André. She does in time, especially when she delivers a girl. Time passes, and she’s pregnant with a second child and then a third. Everyone gets along amid the shrieks and cluttered toys, but the rooms start to shrink, as does Murielle’s smile. The men become snappish, demanding. André promises to hire a housekeeper who never materializes, perhaps because he knows Murielle, however tired, will do the work. And then, suddenly, she’s pregnant again.

By the time the fourth child arrives it becomes excruciatingly clear who those tiny coffins were for. That may make “Our Children” sound unbearable, and there’s no denying how tough it can be to watch a family melodrama mutate into a horror movie. The performers go a long way to keeping you tethered, particularly Ms. Dequenne, an exciting, sympathetic actor who played the title character in Jean-Pierre and Luc Dardenne’s “Rosetta.” (Mr. Rahim and Mr. Arestrup riffed on a different kind of perverse father-son dynamic in “A Prophet.”) Much like the Dardennes, Mr. Joachim holds to the truth that the personal is political, which is why this isn’t simply a movie about a woman and an unspeakable crime, but also an exploration of the power and cruelty that brought her to that very dark place.